Harrison Susan, Grace James B
Department of Environmental Science and Policy, University of California, Davis, California 95616, USA.
Am Nat. 2007 Aug;170 Suppl 2:S5-15. doi: 10.1086/519010.
The unresolved question of what causes the observed positive relationship between large-scale productivity and species richness has long interested ecologists and evolutionists. Here we examine a potential explanation that we call the biogeographic affinity hypothesis, which proposes that the productivity-richness relationship is a function of species' climatic tolerances that in turn are shaped by the earth's climatic history combined with evolutionary niche conservatism. Using botanical data from regions and sites across California, we find support for a key prediction of this hypothesis, namely, that the productivity-species richness relationship differs strongly and predictably among groups of higher taxa on the basis of their biogeographic affinities (i.e., between families or genera primarily associated with north-temperate, semiarid, or desert zones). We also show that a consideration of biogeographic affinity can yield new insights on how productivity-richness patterns at large geographic scales filter down to affect patterns of species richness and composition within local communities.
大规模生产力与物种丰富度之间存在着明显的正相关关系，其背后的原因一直悬而未决，这一问题长期以来吸引着生态学家和进化论者的关注。在此，我们探讨一种可能的解释，即生物地理亲和性假说，该假说认为生产力与丰富度的关系是物种气候耐受性的函数，而物种的气候耐受性又受到地球气候历史和进化生态位保守性的共同影响。利用加利福尼亚州各地的区域和地点的植物学数据，我们发现这一假说的一个关键预测得到了支持，即基于生物地理亲和性（即主要与北温带、半干旱或沙漠地带相关的科或属之间），生产力与物种丰富度的关系在高等分类群之间存在显著且可预测的差异。我们还表明，考虑生物地理亲和性可以为大规模地理尺度上的生产力与丰富度模式如何向下过滤影响当地群落内的物种丰富度和组成模式带来新的见解。
